Ice-making apparatuses are used to supply cube ice in commercial operations. Typically, ice-making apparatuses produce clear ice by flowing water on a vertical, freeze surface. The freeze surface is thermally coupled to a refrigerant circuit forming part of a refrigeration system. The freeze surface commonly has freeze surface geometry for defining ice cube shapes. As water flows over the geometrical definitions, it freezes into cube ice.
FIG. 5 illustrates a circuit diagram of a refrigeration system 500 that can be used with an evaporator assembly of an ice-making apparatus.
The refrigeration system 500 includes a compressor 510, a condenser 520, an expansion device 530, a refrigerant circuit 540, and a solenoid 550. The refrigerant circuit 540 is formed in a serpentine shape and is known as an serpentine.
During operation, the ice-making apparatus alternates between a freeze cycle and a harvest cycle. During the freeze cycle when ice cubes are produced, water is routed over a freeze portion (not shown) on which the water freezes into ice cubes. At the same time, the compressor 510 receives low-pressure, substantially gaseous refrigerant from the refrigerant circuit 540, pressurizes the refrigerant, and discharges high-pressure, substantially gaseous refrigerant to the condenser 520. Provided the solenoid valve 550 is closed, the high-pressure, substantially gaseous refrigerant is routed through the condenser 520. In the condenser 520, heat is removed from the refrigerant, causing the substantially gaseous refrigerant to condense into a substantially liquid refrigerant.
After exiting the condenser 520, the high-pressure, substantially liquid refrigerant encounters the expansion device 530, which reduces the pressure of the substantially liquid refrigerant for introduction into the refrigerant circuit 540. The low-pressure, liquid refrigerant enters the refrigerant circuit 540 where the refrigerant absorbs heat and vaporizes as the refrigerant passes therethrough. This low-pressure, liquid refrigerant in the refrigerant circuit 540 cools the freeze portion, which is thermally coupled to the refrigerant circuit 540, to form the ice on the freeze portion. Low-pressure, substantially gaseous refrigerant exits the refrigerant circuit 540 for re-introduction into the compressor 510.
To harvest the ice cubes, the freeze cycle ends and water is stopped from flowing over the freeze portion. The solenoid 550 is then opened to allow high-pressure, substantially hot gaseous refrigerant discharged from the compressor 510 to enter the refrigerant circuit 540. The high-pressure, substantially hot gaseous refrigerant in the refrigerant circuit 540 defrosts the freeze portion to facilitate the release of ice from the freeze portion. The individual ice cubes eventually fall off of the freeze portion into an ice bin (not shown). At this time, the harvest cycle ends, and the freeze cycle is restarted to create more ice cubes.
Known evaporator assembly designs require a large amount of copper and individual parts to create the assembly. A typical evaporator assembly will have 48 to 75 parts. Also adding to the cost of the assembly is the need for all copper surfaces to be plated with nickel to meet food equipment sanitation requirements. The plating process is complex and it is difficult to maintain manufacturing control, thus increasing the likelihood of premature failure and increased warranty expense.
Also, known evaporator assemblies need to be cleaned periodically to remove the buildup of minerals from hard water and disinfected for bacterial growth. Evaporator assemblies have dividers on the freeze surface used to separate ice growth and define pockets for ice cubes. The dividers make it difficult to clean the freeze surfaces completely because of the small size and depth of the cube cell pockets. Some evaporator assemblies may have as many as 400 cube cell pockets. Another difficult to clean area of known evaporator assemblies is where the refrigerant circuit 540 connects to the freeze surface. This area is not accessible for manual cleaning because of the evaporator assembly construction or its positioning in the ice-making apparatus cabinet.
Ice-making apparatus performance is evaluated by two different measures: (1) ice-making capacity in a 24-hour period; and (2) kilowatt hours per 100 pounds of ice produced. Ice harvest times have a direct effect on machine performance. Ice-making apparatuses with longer harvest times time spend less time making ice and are more susceptible to liquid refrigerant slugging the compressor and reducing its functional life. One challenge to releasing the ice more quickly is the use of dividers on the freeze surface for ice cube separation. Ice clings to the dividers, the ice pieces do not release consistently, thereby extending the amount of time required to release the ice. Because of these challenges, manufactures assist the release of ice using mechanical push rods, pressurized air, or potable water supplied to the inside of the evaporator assembly. It is also desirable to harvest all ice at the same time so the machine mode can immediately switch back to ice making. To harvest all of the ice at one time evaporator assemblies bridge all of the cubes together into a slab. However, the ice bridge makes it difficult to break the slab into individual cubes.
Further, prior evaporator assemblies attach the refrigerant circuit 540 directly to the ice freeze surface material on which the ice is formed. This design requires the evaporator assembly to have freeze surface divider geometry or additional parts to manage ice growth and define cube shape.